Colorectal cancer is the third most common cancer worldwide, accounting for about 10% of all cancer cases diagnosed annually. It is a deadly disease with serious impact on human health. During the year of 2012, for instance, 1.4 million new cases of colorectal cancers were diagnosed globally, and nearly 700,000 deaths from the disease were recorded. Incidence of colorectal cancers is substantially higher in developed countries, where more than 65% of cases are found. Men are more likely to suffer from this disease than women.
Diagnosis of colorectal cancer can be challenging. Although family history may provide useful implications for diagnosis, vast majority of the disease (greater than 75-95%) occurs in people with little or no genetic risk. Symptoms of colorectal cancer also can vary significantly, depending on the location of the cancer in the colon, and whether it has spread elsewhere in the body. Depending on how early colorectal cancer is diagnosed, its prognosis can vary from very good to very grim: it is highly curable with surgery when the cancer mass remains confined within the wall of the colon; on the other hand, once colorectal cancer has spread, it is usually not curable, with medical intervention focusing on improving quality of life and alleviating symptoms. On average, the 5-year survival rate in the United States is around 65%.
Because of the high prevalence of colorectal cancer and the vital importance of early diagnosis on patients' life expectancy, there exists an urgent need for new and more effective methods to diagnose, monitor, and treat colorectal cancer. This invention fulfills this and other related needs.